Apparatuses and methods consistent with exemplary embodiments relate to a supply modulator, and more particularly, to a supply modulator generating a plurality of driving voltages having different levels and a communication device including the supply modulator.
Wireless communication devices such as smartphones, tablets, and Internet of Things (IoT) devices use WCDMA (3G), LTE, and LTE Advanced (4G) technology for high speed communication. As communication technology has been increasingly advancing, transmission or reception signals having a higher peak-to-average power ratio (PAPR) and a greater bandwidth are required. Thus, if a power supply of a power amplifier of a transmission end is connected to a battery, the efficiency of the power amplifier decreases. In order to increase the efficiency of a power amplifier having a high PAPR and a wide bandwidth, Average Power Tracking (APT) or Envelope Tracking (ET) is used. When using the ET technique, the efficiency and linearity of a power amplifier may be enhanced. A chip that supports the APT technique or ET technique is referred to as a supply modulator (SM).